MAX1652MAX1655 19-1357 Rev 1 7/98 High-Efficiency, PWM, Step-Down DC-DC Controllers in 16-Pin QSOP General Description Features The MAX1652MAX1655 are high-efficiency, pulse- 96% Efficiency width-modulated (PWM), step-down DC-DC controllers Small, 16-Pin QSOP Package in small QSOP packages. The MAX1653/MAX1655 also (half the size of a 16-pin narrow SO) come in 16-pin narrow SO packages that are pin- Pin-Compatible with MAX797 (MAX1653/MAX1655) compatible upgrades to the popular MAX797. Improve- ments include higher duty-cycle operation for better Output Voltage Down to 1V (MAX1655) dropout, lower quiescent supply currents for better 4.5V to 30V Input Range light-load efficiency, and an output voltage down to 1V 99% Duty Cycle for Lower Dropout (MAX1655). 170A Quiescent Supply Current The MAX1652MAX1655 achieve up to 96% efficiency and deliver up to 10A using a unique Idle Mode syn- 3A Logic-Controlled Shutdown chronous-rectified PWM control scheme. These devices Dual, N-Channel, Synchronous-Rectified Control automatically switch between PWM operation at heavy Fixed 150kHz/300kHz PWM Switching, loads and pulse-frequency-modulated (PFM) operation or Synchronized from 190kHz to 340kHz at light loads to optimize efficiency over the entire out- put current range. The MAX1653/MAX1655 also feature Programmable Soft Start logic-controlled, forced PWM operation for noise-sensi- Low-Cost Secondary Outputs (MAX1652/MAX1654) tive applications. All devices operate with a selectable 150kHz/300kHz switching frequency, which can also be synchronized Ordering Information to an external clock signal. Both external power switch- es are inexpensive N-channel MOSFETs, which provide PART TEMP. RANGE PIN-PACKAGE low resistance while saving space and reducing cost. MAX1652EEE -40C to +85C 16 QSOP The MAX1652 and MAX1654 have an additional feed- MAX1653ESE -40C to +85C 16 Narrow SO back pin that permits regulation of a low-cost second MAX1653EEE -40C to +85C 16 QSOP output tapped from a transformer winding. The MAX1654EEE -40C to +85C 16 QSOP MAX1652 provides an additional positive output. The MAX1654 provides an additional negative output. MAX1655ESE -40C to +85C 16 Narrow SO The MAX1652MAX1655 have a 4.5V to 30V input volt- MAX1655EEE -40C to +85C 16 QSOP age range. The MAX1652/MAX1653/MAX1654s output range is 2.5V to 5.5V while the MAX1655s output range extends down to 1V. An evaluation kit (MAX1653EVKIT) is available to speed designs. Selection Guide Applications FEEDBACK SPECIAL PART COMPATIBILITY Notebook Computers VOLTAGE (V) FEATURE PDAs Regulates positive Same pin order Cellular Phones MAX1652 2.5 secondary voltage as MAX796, but (such as +12V) smaller package Hand-Held Computers Logic-controlled, Pin-compatible Handy-Terminals MAX1653 2.5 low-noise mode with MAX797 Mobile Communicators Regulates negative Same pin order Distributed Power MAX1654 2.5 secondary voltage as MAX799, but (such as -5V) smaller package Low output volt- Pin compatible Pin Configurations appear at end of data sheet. ages (1V to 5.5V) with MAX797 MAX1655 1 logic-controlled, (except for feed- Idle Mode is a trademark of Maxim Integrated Products. low-noise mode back voltage) Maxim Integrated Products 1 For free samples & the latest literature: High-Efficiency, PWM, Step-Down DC-DC Controllers in 16-Pin QSOP ABSOLUTE MAXIMUM RATINGS V+ to GND..............................................................-0.3V to +36V REF Short Circuit to GND...........................................Continuous GND to PGND .......................................................-0.3V to +0.3V VL Output Current...............................................+50mA to -1mA VL to GND ................................................................-0.3V to +6V REF Output Current...............................................+5mA to -1mA BST to GND............................................................-0.3V to +36V Continuous Power Dissipation (T = +70C) A DH to LX .....................................................-0.3V to (BST + 0.3V) SO (derate 8.70mW/C above +70C) .......................696mW LX to BST..................................................................-6V to +0.3V QSOP (derate 8.3mW/C above +70C) ....................667mW SHDN to GND...............................................-0.3V to (V+ + 0.3V) Operating Temperature Range SYNC, SS, REF, SECFB, SKIP, FB to GND...-0.3V to (VL + 0.3V) MAX165 E E ..................................................-40C to +85C DL to PGND ..................................................-0.3V to (VL + 0.3V) Storage Temperature Range .............................-65C to +160C CSH, CSL to GND ....................................................-0.3V to +6V Lead Temperature (soldering, 10sec) .............................+300C VL Short Circuit to GND..............................................Momentary Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS (V+ = +15V, GND = PGND = 0V, SYNC = REF, I = I = 0A, T = 0C to +85C, unless otherwise noted.) VL REF A PARAMETER CONDITIONS MIN TYP MAX UNITS 3.3V AND 5V STEP-DOWN CONTROLLERS Input Supply Range 4.5 30 V 0 < (CSH - CSL) < 80mV, FB = VL, 6V < V+ < 30V, 5V Output Voltage (CSL) 4.85 5.06 5.25 V includes line and load regulation 0 < (CSH - CSL) < 80mV, FB = 0V, 4.5V < V+ < 30V, 3.3V Output Voltage (CSL) 3.20 3.34 3.46 V includes line and load regulation MAX1655 1 5.5 Nominal Adjustable Output External resistor divider V MAX1652/MAX1653/ Voltage Range 2.5 5.5 MAX1654 MAX1655 0.97 1.00 1.03 CSH - CSL = 0V, CSL = FB, Feedback Voltage V MAX1652/MAX1653/ SKIP = 0V, 4.5V < V+ < 30V 2.43 2.50 2.57 MAX1654 0 < (CSH - CSL) < 80mV 2 Load Regulation % 25mV < (CSH - CSL) < 80mV 1.2 Line Regulation 6V < V+ < 30V 0.03 0.06 %/V CSH - CSL, positive 80 100 120 Current-Limit Voltage mV CSH - CSL, negative -50 -100 -160 SS Source Current V = 0V 2.5 4.0 6.5 A SS SS Fault Sink Current V = 4V 2.0 mA SS FLYBACK/PWM CONTROLLER Falling edge, rising edge, hysteresis = 22mV (MAX1652) 2.45 2.50 2.55 SECFB Regulation Setpoint V Rising edge, falling edge, hysteresis = 22mV (MAX1654) -0.05 0 0.05 INTERNAL REGULATOR AND REFERENCE VL Output Voltage SHDN = 2V, 0 < I < 25mA, 5.5V < V+ < 30V 4.7 5.0 5.3 V VL VL Fault Lockout Voltage Rising edge, falling edge hysteresis = 50mV 3.8 3.9 4.0 V VL/CSL Switchover Voltage Rising edge, falling edge hysteresis = 60mV 4.2 4.5 4.7 V 2 MAX1652MAX1655